Aqueous adhesive composition based on polyaldehyde and polyphenol

ABSTRACT

An aqueous adhesive composition includes: a phenol/aldehyde resin; and an unsaturated elastomer latex. The phenol/aldehyde resin is based on: an aromatic polyaldehyde bearing at least two aldehyde functional groups and including at least one aromatic nucleus; and a polyphenol including at least one aromatic nucleus. If there is just one aromatic nucleus, the nucleus bears two or three hydroxyl functional groups in a meta position with respect to each other or with respect to one another, with a remainder of the nucleus being unsubstituted. If there are plural aromatic nuclei, at least two of the nuclei each bear two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another, with two positions ortho to at least one of these hydroxyl functional groups being unsubstituted. The adhesive composition is useable to adhere a textile material to a crosslinkable rubber composition.

FIELD OF THE INVENTION

The field of the present invention is that of textile materials andadhesive compositions or “adhesives” intended to make such textilematerials adhere to unsaturated rubber matrices, such as those commonlyused in rubber articles or semi-finished products.

The present invention relates more particularly to textile materialssized with adhesive layers based on a phenol/aldehyde resin, inparticular to sized textile materials capable of reinforcing tyrestructures.

RELATED ART

It has been known for a very long time to make textile materials adhereto diene elastomer compositions by virtue of the use of adhesives knownunder the name “RFL” (for resorcinol/formaldehyde latex), for examplefor the adhesive bonding of rubber compositions to textile cords made ofpolyester or polyamide, such as those normally used in tyres (see, forexample, U.S. Pat. No. 2,561,215 and U.S. Pat. No. 3,817,778). These RFLadhesives comprise, in a well-known way, a thermosetting phenolic resin,obtained by the condensation of resorcinol with formaldehyde, and one ormore latexes of diene rubber in aqueous solution.

Experience shows that the above RFL adhesives confer excellent adhesionof textile materials to crosslinkable rubber compositions.

However, these RFL adhesives are not without disadvantage; in particularthey comprise formaldehyde as base substance, which substance it isdesirable in the long run to reduce in, indeed even to eliminate from,adhesive compositions because of the recent changes in Europeanregulations regarding this type of compound.

Thus, the designers of rubber articles, in particular tyremanufacturers, today have the objective of finding novel adhesivesystems or novel textile materials which make it possible to overcomethe abovementioned disadvantage.

BRIEF DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In point of fact, during their research studies, the Applicant Companieshave discovered an aqueous adhesive composition not using formaldehydewhich makes it possible to meet the above objective.

Thus, a first subject-matter of the invention relates to an aqueousadhesive composition comprising at least, on the one hand, A) aphenol/aldehyde resin and, on the other hand, B) an unsaturatedelastomer latex, characterized in that the phenol/aldehyde resin isbased on at least:

-   -   one aromatic polyaldehyde bearing at least two aldehyde        functional groups, comprising at least one aromatic nucleus;    -   one polyphenol comprising one or more aromatic nucleus/nuclei,        it being understood that:        -   in the case of just one aromatic nucleus, the latter bears            two or three hydroxyl functional groups in the meta position            with respect to each other or with respect to one another,            the remainder of the aromatic nucleus being unsubstituted;        -   in the case of several aromatic nuclei, at least two of them            each bear two or three hydroxyl functional groups in the            meta position with respect to each other or with respect to            one another, it being understood that the two positions            ortho to at least one of these hydroxyl functional groups            are unsubstituted.

Another subject-matter of the invention relates to the use of theaqueous adhesive composition according to the invention to make atextile material adhere, by curing, to a crosslinkable rubbercomposition, and also to a textile material, at least a portion of whichis coated with an adhesive layer, characterized in that the said layercomprises an aqueous adhesive composition according to the invention.

The invention also relates to a process for the manufacture of a textilematerial according to the invention, characterized in that it comprisesat least one stage of deposition, on a starting textile material, of anadhesive composition in accordance with the invention.

The invention also relates to the use of the textile material of theinvention as reinforcing element for rubber articles or semi-finishedproducts, in particular tyres, especially those intended to equip motorvehicles of passenger type, SUVs (“Sport Utility Vehicles”), two-wheelvehicles (in particular bicycles and motorcycles), aircraft, as forindustrial vehicles chosen from vans, heavy-duty vehicles, that is tosay, underground trains, buses, heavy road transport vehicles (lorries,tractors, trailers) or off-road vehicles, such as heavy agriculturalvehicles or earthmoving equipment, or other transportation or handlingvehicles.

The invention also relates, per se, to any rubber composite (article orsemi-finished product), in particular any tyre, before and after curing(for final crosslinking or vulcanization), comprising a textile materialaccording to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its advantages will be easily understood in the lightof the description and implementational examples, which follow,considered in conjunction with the SOLE FIGURE attached hereto, whichschematically shows a radial section of a tyre according to anembodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

I—Formulation of the Aqueous Adhesive Composition

In the present description, unless expressly indicated otherwise, allthe percentages (%) shown are % by weight.

“Diene” elastomer (or, without distinction, rubber) is understood tomean an elastomer resulting at least in part (that is to say, ahomopolymer or a copolymer) from diene monomer(s) (i.e., monomersbearing two conjugated or non-conjugated carbon-carbon double bonds).“Isoprene elastomer” is understood to mean an isoprene homopolymer orcopolymer, in other words a diene elastomer selected from the groupconsisting of natural rubber (NR), synthetic polyisoprenes (IRs),various isoprene copolymers and the mixtures of these elastomers.

Furthermore, any interval of values denoted by the expression “between aand b” represents the range of values extending from more than a to lessthan b (that is to say, limits a and b excluded), whereas any intervalof values denoted by the expression “from a to b” means the range ofvalues extending from a up to b (that is to say, including the strictlimits a and b).

The expression “composition based on” should, of course, be understoodas meaning a composition comprising the mixture and/or the reactionproduct of the various base constituents used for this composition, itbeing possible for some of them to be intended to react or capable ofreacting with one another or with their immediate chemical surroundings,at least partly, during the various phases of manufacture of thecomposition, of the textile material or of the composites or finishedarticles comprising such composites, in particular during a curingstage.

The aqueous adhesive composition according to the invention thuscomprises at least, on the one hand, A) a (at least one) phenol/aldehyderesin and, on the other hand, B) a (at least one) unsaturated elastomerlatex; this phenol/aldehyde resin is, for its part, based on at leastone (that is to say, one or more) aromatic polyaldehyde and at least one(that is to say, one or more) polyphenol, which constituents will bedescribed in detail below.

I.1—Aromatic Polyaldehyde

The first essential constituent of the phenol/aldehyde resin is anaromatic polyaldehyde bearing at least two aldehyde functional groups,comprising at least one aromatic nucleus. According to a preferredembodiment, it is the said aromatic nucleus which bears the aldehydefunctional groups, it being possible for the latter to be in the ortho,meta or para position on the aromatic nucleus.

Preferably, the aromatic nucleus of the polyaldehyde is a benzenenucleus. More preferably, this polyaldehyde is selected from the groupconsisting of 1,2-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde,1,4-benzenedicarboxaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde andthe mixtures of these compounds.

More preferably still, the aromatic polyaldehyde used is1,4-benzenedicarboxaldehyde, also called terephthaldehyde, as a reminderof expanded chemical formula:

I.2—Polyphenol

The second essential constituent of the phenol/aldehyde resin is apolyphenol comprising one or more aromatic nucleus/nuclei.

In the case of a polyphenol comprising just one aromatic nucleus, thelatter bears two or three hydroxyl functional groups in the metaposition with respect to each other (in the case of two functionalgroups) or with respect to one another (in the case of three functionalgroups), the remainder of the aromatic nucleus being by definitionunsubstituted; this is understood to mean that the other carbon atoms ofthe remainder of the aromatic nucleus (those other than the carbon atomsbearing hydroxyl functional groups) bear a simple hydrogen atom.

Mention may in particular be made, as preferred example of polyphenolcomprising just one aromatic nucleus, of resorcinol, as a reminder ofexpanded formula:

In the case of a polyphenol comprising several (two or more than two)aromatic nuclei, at least two of them each bear two or three hydroxylfunctional groups in the meta position with respect to each other (inthe case of two functional group) or with respect to one another (in thecase of three functional groups), it being understood that the twopositions ortho to at least one of these hydroxyl functional groups areunsubstituted; this is understood to mean that the two carbon atomslocated on either side of (in the ortho position to) the hydroxylatedcarbon atom (i.e., bearing the hydroxyl functional group) bear a simplehydrogen atom.

As preferred examples, in the case where the polyphenol moleculecomprises several aromatic nuclei, at least two of these aromaticnuclei, which are identical or different, are selected from those ofgeneral formulae:

in which the Z symbols, which are identical or different, if they areseveral on the same aromatic nucleus, represent an atom (for example,carbon, sulphur or oxygen) or a connecting group, by definition at leastdivalent, which connects at least these two aromatic nuclei to theremainder of the polyphenol molecule.

According to a specific and preferred embodiment of the invention, thepolyphenol is, for example, a flavonoid, characterized, as a reminder,by a structure based on 15 carbon atoms, formed by two benzene ringsconnected via three carbon atoms. More particularly, the flavonoid usedis 2′,4′,3,5,7-pentahydroxyflavone, also called “morin”, of formula (II)below:

It is noted that this compound is a polyphenol comprising two aromaticnuclei (of respective formulae I-c and I-d above), each of which indeedbears two hydroxyl functional groups in the meta position with respectto each other, the two positions ortho to at least one of these twohydroxyl functional groups being unsubstituted.

According to another specific and preferred embodiment of the invention,the polyphenol is, for example, phloroglucide, also called2,4,6,3′,5′-biphenylpentol, of following expanded formula:

It is noted that this compound is a polyphenol comprising two aromaticnuclei (of respective formulae I-a and I-b above), each of which indeedbears at least two (in the case in point, one bears two and the otherbears three) hydroxyl functional groups in the meta position withrespect to each other, the two positions ortho to at least one of thesetwo hydroxyl functional groups being unsubstituted.

I.3—Unsaturated Elastomer Latex

It should be remembered that a latex is a stable dispersion ofmicroparticles of elastomer(s) in suspension in an aqueous solution.

Unsaturated (that is to say, bearing carbon-carbon double bonds)elastomer latexes, in particular diene elastomer latexes, are well knownto a person skilled in the art. They constitute in particular theelastomeric base of the RFL adhesives described in the introduction tothe present account.

In accordance with the invention, the unsaturated elastomer of the latexis preferably a diene elastomer, more preferably a diene elastomerselected from the group consisting of polybutadienes, butadienecopolymers, polyisoprenes, isoprene copolymers and the mixtures of theseelastomers. It is more preferably still selected from the groupconsisting of butadiene copolymers, vinylpyridine/styrene/butadieneterpolymers, natural rubber and the mixtures of these elastomers.

I.4—Additives—Manufacture of the Aqueous Adhesive Composition

The aqueous adhesive composition in accordance with the invention and/orits phenol/aldehyde resin and/or its starting unsaturated elastomerlatex can, of course, comprise all or some of the additives normal foraqueous adhesive compositions, such as those used in conventional RFLadhesives; mention will be made, for example, of bases, such as aqueousammonia, sodium hydroxide, potassium hydroxide or ammonium hydroxide,colourants, fillers, such as carbon black or silica, antioxidants orother stabilizers.

Typically, during a first manufacturing stage, the resin itself isprepared by gradually mixing the polyphenol and the aromaticpolyaldehyde in a basic solvent, such as an aqueous sodium hydroxidesolution, preferably having a pH of between 9 and 13, more preferablybetween 10 and 12. The combined constituents are mixed with stirring fora time which can vary according to the temperature used and the specificcomposition targeted, for example for a period of time which can varybetween 1 min and 6 h, at a temperature of between 20° C. and 90° C.,preferably between 20° C. and 60° C.

The ratio by weight of polyphenol to polyaldehyde is preferably between0.1 and 3, more preferably between 0.25 and 2.

The phenol/aldehyde resin, thus pre-condensed, is generally diluted inwater before being added to the unsaturated elastomer latex or latexes(if there are several), in order to form the aqueous adhesivecomposition of the invention, according to a general procedure which iswell-known to a person skilled in the art in the field of RFL adhesives.

For example, the constituents of the adhesive composition are added inthe following order: the water, possible water-soluble additives (forexample aqueous ammonia), the latex or latexes (order unimportant), thephenol/aldehyde resin (diluted). The combination is mixed with stirringfor 1 to 30 min, for example at 20° C.

During a final manufacturing stage, the aqueous adhesive composition isgenerally stored at ambient temperature (23° C.) for a maturing timewhich can typically vary from 1 to several hours, indeed even severaldays, before it is finally used.

In the final adhesive composition thus prepared, the content ofphenol/aldehyde resin as dry matter preferably represents between 5% and60% by weight, more preferably between 10% and 30% by weight, of theadhesive composition dry matter.

For its part, the content of unsaturated elastomer (that is to say, thedry matter of the latex or latexes) is preferably between 40% and 95% byweight, more preferably between 70% and 90% by weight, of the dry matterof the adhesive composition.

The ratio by weight of the resin dry matter to the latex dry matter ispreferably between 0.1 and 2.0, more preferably between 0.15 and 1.0.

The water content of the aqueous adhesive composition of the inventionis preferably between 60% and 90%, more preferably between 60% and 85%.

II—Textile Material and Composite of the Invention

As indicated above, the present invention also relates to the use of theaqueous adhesive composition described above for the adhesive bonding ofany textile material to an unsaturated rubber composition, for formationof a reinforced rubber composite of such a material, and also, as such,to the textile material, at least a portion of which is coated with anadhesive composition according to the invention.

II.1—Definitions; Examples of Textile Materials

In the present patent application, by definition, “textile” or “textilematerial” is understood to mean, in a way well known to a person skilledin the art, any material made of a substance other than a metallicsubstance, whether natural or synthetic, which is capable of beingtransformed into thread, fibre or film by any appropriate transformationprocess. Mention may be made, for example, without the examples belowbeing limiting, of a polymer spinning process, such as, for example,melt spinning, solution spinning or gel spinning

This textile material can consist of a thread or fibre, a ribbon orfilm, or also of a fabric produced from threads or fibres, for example awoven fabric with warp threads and weft threads, or else a twill fabricwith cross threads.

Preferably, this textile material of the invention is selected from thegroup consisting of films, monofilaments (or individual threads),multifilament fibres, assemblies of such threads or fibres, and mixturesof such materials. It is more particularly a monofilament, amultifilament fibre or a folded yarn.

The term “thread” or “fibre” is generally understood to mean anyelongate element of great length relative to its cross section, whateverthe shape, for example circular, oblong, rectangular, square, or evenflat, of this cross section, it being possible for this thread to bestraight or not straight, for example twisted or wavy. The largestdimension of its cross section is preferably less than 5 mm, morepreferably less than 3 mm.

This thread or fibre may take any known form. For example, it may be anindividual monofilament of large diameter (for example and preferablyequal to or greater than 50 μm), a multifilament fibre (consisting of aplurality of individual filaments of small diameter, typically less than30 μm), a textile folded yarn or cord formed from several textile fibresor monofilaments twisted or cabled together, or else an assembly, groupor row of threads or fibres, such as, for example, a band or stripcomprising several of these monofilaments, fibres, folded yarns or cordsgrouped together, for example aligned along a main direction, whetherstraight or not.

The term “film” or “ribbon” is generally understood to mean an elongateelement of great length relative to its cross section, the cross sectionof which has an aspect ratio (width to thickness) of greater than 5,preferably of greater than 10, and the width of which is preferably atleast equal to 3 mm, more preferably at least equal to 5 mm.

The aqueous adhesive composition of the invention can be applied to anytextile material as described above and capable of reinforcing rubberarticles, such as tyres, including textile materials made of organic orpolymeric substance, such as made of inorganic substance.

Mention will be made, as examples of inorganic substances, of glass orcarbon.

The invention is preferably implemented with materials made of polymericsubstance, of both the thermoplastic and non-thermoplastic type.

Mention will be made, as examples of polymeric substances of thenon-thermoplastic type, for example, of aramid (aromatic polyamide) andcellulose, both natural and artificial, such as cotton, rayon, flax orhemp.

Mention will preferably be made, as examples of polymeric substances ofthe thermoplastic type, of aliphatic polyamides and of polyesters.Mention may in particular be made, among the aliphatic polyamides, ofthe polyamides PA-4,6, PA-6, PA-6,6, PA-11 or PA-12. Mention may bemade, among the polyesters, for example, of PET (polyethyleneterephthalate), PEN (polyethylene naphthalate), PBT (polybutyleneterephthalate), PBN (polybutylene naphthalate), PPT (polypropyleneterephthalate) and PPN (polypropylene naphthalate).

II.2—Manufacture of the Textile Material and of the Composite

The textile material of the invention can be prepared according to asizing process, characterized in that it comprises at least one stage ofdeposition, on the starting (initial) textile material, of an adhesivecomposition in accordance with the invention.

The stage of deposition of the adhesive composition on the initialtextile material (starting textile material) can be carried outaccording to any appropriate method, in particular by any known coatingtechnique, such as, for example, spraying, impregnation by dipping,forward progression in a bath or other equivalent technique for thedeposition of a thin or ultra-thin film of adhesive, or also by acombination of one or more of these techniques.

The weight of dry matter of the aqueous adhesive composition depositedon one kilogram of textile material is preferably between 5 and 100 g,more preferably between 30 and 70 g and more preferably still between 40and 60 g.

The invention also applies to the cases where the starting textilematerial has been precoated with an adhesion primer, such as thosecommonly used by a person skilled in the art for the pre-sizing ofcertain textile fibres (e.g., PET or aramid fibres). The fibres, thusprecoated, are then subjected to a subsequent and definitive sizing withthe aqueous adhesive composition according to the invention.

After the stage, described above, of deposition of the adhesivecomposition, the sized material is subjected to a first heat treatment,targeted at removing any solvent or water, at a temperature ofpreferably between 110° C. and 260° C., more preferably between 130° C.and 250° C., for example by passing through a tunnel oven, typicallywith a length of several metres, such as those commonly used for theheat treatment after sizing of the textile materials with an RFLadhesive.

The invention also relates to the textile material obtained afterdrying, that is to say, after a heat treatment targeted at removing thewater from the textile material according to the invention, at least aportion of which is coated with an adhesive layer comprising an adhesivecomposition according to the invention.

The anhydrous material thus obtained is then subjected to a second heattreatment in order to terminate the crosslinking of the adhesivecomposition, preferably carried out in air in a tunnel oven as describedabove. The treatment temperature is preferably between 150° C. and 350°C. The treatment times are from a few seconds to a few minutes,according to the circumstances (for example, between 10 s and 10 min).

Where appropriate, a person skilled in the art will know how to adjustthe temperature and the duration of the heat treatment above accordingto the particular operating conditions of the invention, especiallyaccording to the exact nature of the textile material manufactured, inparticular depending on whether the treatment is on monofilaments,multifilament fibres, folded yarns consisting of several fibres twistedtogether, or films. In particular, a person skilled in the art will havethe advantage of varying the treatment temperature and treatment time soas to find, by successive approximations, the operating conditionsgiving the best adhesion results for each particular embodiment of theinvention.

Thus sized, the textile material of the invention is preferably intendedto adhere to an unsaturated rubber composition, such as a diene rubber,in order to form a reinforced rubber composite which constitutes anothersubject-matter of the invention.

This rubber composite of the invention can be prepared according to aprocess comprising at least the following stages:

-   -   during a first stage, combining at least a portion of the        textile material according to the invention with an unsaturated        (crosslinkable) rubber composition, in order to form a rubber        composite reinforced with the textile material;    -   then, during a second stage, crosslinking the composite thus        formed by curing, preferably under pressure.

The invention thus applies to any type of rubber composite capable ofbeing obtained by the process described above, comprising at least amatrix made of crosslinkable rubber composition, in particular dienerubber composition, bonded to the textile material via an adhesiveinterphase based on the adhesive composition according to the invention.

The diene elastomer of the composite is preferably selected from thegroup consisting of polybutadienes (BRs), natural rubber (NR), syntheticpolyisoprenes (IRs), butadiene/styrene copolymers (SBRs),isoprene/butadiene copolymers (BIRs), isoprene/styrene copolymers(SIRs), butadiene/styrene/isoprene copolymers (SBIRs) and the mixturesof these elastomers. A preferred embodiment consists in using an“isoprene” elastomer, that is to say an isoprene homopolymer orcopolymer, in other words a diene elastomer selected from the groupconsisting of natural rubber (NR), synthetic polyisoprenes (IRs), thevarious copolymers of isoprene and the mixtures of these elastomers. Theisoprene elastomer is preferably natural rubber or a syntheticpolyisoprene of the cis-1,4 type.

II.3—Application in Tyres

The textile material of the invention can advantageously be used toreinforce tyres for all types of vehicles, in particular passengervehicles or industrial vehicles, such as heavy-duty vehicles.

By way of example, the single appended figure represents verydiagrammatically (without observing a specific scale) a radial sectionof a tyre in accordance with the invention for a vehicle of thepassenger type.

This tyre 1 comprises a crown 2 reinforced by a crown reinforcement orbelt 6, two sidewalls 3 and two beads 4, each of these beads 4 beingreinforced with a bead thread 5. The crown 2 is surmounted by a tread,not represented in this diagrammatic figure. A carcass reinforcement 7is wound around the two bead threads 5 in each bead 4, the turn-up 8 ofthis reinforcement 7 being, for example, positioned towards the outsideof the tyre 1, which is here represented fitted onto its wheel rim 9.The carcass reinforcement 7 is, in a way known per se, composed of atleast one ply reinforced by “radial” cords, for example textile cords,that is to say that these cords are positioned virtually parallel to oneanother and extend from one bead to the other so as to form an angle ofbetween 80° and 90° with the median circumferential plane (planeperpendicular to the axis of rotation of the tyre which is locatedhalfway between the two beads 4 and passes through the middle of thecrown reinforcement 6).

This tyre 1 of the invention has, for example, the essentialcharacteristic that at least a crown reinforcement 6 and/or its carcassreinforcement 7 comprises a textile material according to the invention.According to another possible implementational example of the invention,it is, for example, the bead threads 5 which might be composed, in allor in part, of a textile material according to the invention.

Of course, the invention relates to the objects described above, namelythe textile material and the rubber composite, such as tyre, comprisingit, both in the raw state (before curing or vulcanization) and in thecured state (after curing).

III—Examples of the Implementation of the Invention

III.1—Test 1: Adhesion of Polyamide Textile Cords

These tests demonstrate that the adhesion, to a diene elastomercomposition, of polyamide textile cords sized with an aqueous adhesivecomposition according to the invention is equivalent, indeed even insome cases improved, in comparison with cords sized with a conventionaladhesive composition of the RFL type.

For this, four aqueous adhesive compositions were prepared as indicatedabove, three in accordance with the invention (hereinafter denoted C-1.2to C-1.4) and one not in accordance with the invention (controlcomposition, hereinafter denoted C-1.1). Their formulations (expressedas percentage by weight) are presented in the appended Table 1. Theamounts listed in this table are those of the constituents in the drystate, with respect to a total of 100 parts by weight of aqueousadhesive composition (that is to say, the constituents plus the water).

The adhesive composition C-1.1 is a control composition, of RFL type,commonly used for the adhesion of polyamide cords to a rubbercomposition. This adhesive composition is based on resorcinol andformaldehyde.

The aqueous adhesive composition C-1.2 according to the invention isbased on morin and 1,4-benzenedicarboxaldehyde.

The aqueous adhesive compositions C-1.3 and C-1.4 according to theinvention are based on phloroglucide and respectively on1,4-benzenedicarboxaldehyde and 1,3-benzenedicarboxaldehyde.

These adhesive compositions C-1.1 to C-1.4 are furthermore all based onnatural rubber (NR) latex, styrene/butadiene copolymer (SBR) latex andvinylpyridine/styrene/butadiene (VPSBR) latex.

The polyamide (polyamide-6,6) cords consist of folded yarns comprisingtwo strands of 140×2 (count of each strand equal to 140 tex) and 250/250(twist in t/m) construction; they were sized with each of these 4aqueous adhesive compositions C-1.1 to C-1.4 and then dried in a dryingoven at 180° C. for 60 s. The adhesive composition was then crosslinkedby passing the textile cords through a treatment oven at 230° C. for 60s. The combination was then rendered integral, by curing, with a naturalrubber composition by virtue of a vulcanization heat treatment, in orderto form composite test specimens as described below.

The quality of the bonding between the rubber composition and thetextile material is subsequently determined by a test in which the forcenecessary to extract sections of cords made of textile material from thevulcanized rubber composition is measured. This rubber composition is aconventional composition which can be used for the calendering of tyrecarcass reinforcement textile plies, based on natural rubber, carbonblack and standard additives.

More specifically, the vulcanizate is a rubber block consisting of twosheets measuring 200 mm by 4.5 mm and with a thickness of 3.5 mm,applied against each other before curing (the thickness of the resultingblock is then 7 mm) It is during the production of this block that thetextile cords (15 sections in total) are imprisoned between the tworubber sheets in the raw state, an equal distance apart and whileallowing a cord end to project out on either side of these sheets with alength sufficient for the subsequent tensile testing. The blockcomprising the cords is then placed in a suitable mould and then curedunder pressure. The curing temperature and the curing time are adaptedto the intended test conditions and left to the discretion of a personskilled in the art; by way of example, in the present case, the block iscured at 160° C. for 15 min.

On conclusion of the curing, the test specimen, thus consisting of thevulcanized block and the 15 sections of cords, is placed between thejaws of a suitable tensile testing machine in order to make it possibleto test each section individually, at a given rate and a giventemperature (for example, in the present case, at 100 mm/min and 20° C.or 120° C.).

The adhesion levels are characterized by measuring the “tearing-out”force (denoted by F_(max)) for tearing the reinforcers out of the testspecimen. A value greater than that for the control test specimen,arbitrarily set at 100, indicates an improved result, that is to say, agreater tearing-out force than that for the control test specimen. Theresults of the tests carried out on the test specimens are summarized inTable 1.

It is found that the textile cords sized with the adhesive compositionsC-1.2 and C-1.4 according to the invention exhibit a tearing-out forceF_(max) which is particularly high and unexpected for a person skilledin the art as it is very substantially increased (between 14% and 20%),both at ambient temperature (20° C.) and at high temperature (120° C.),in comparison with the reference tearing-out force measured on thecontrol textile cord sized with the conventional “RFL” adhesive. Withregard to the textile cords sized with the composition C-1.3, theyexhibit a tearing-out force F_(max) which is admittedly lower butsignificant and sufficient for a person skilled in the art, comparedwith that measured on the control textile cord sized with this RFLadhesive.

III.2—Test 2: Adhesion of PET Cords

The aim of the tests which follow is to demonstrate the achievement ofsatisfactory adhesion between polyester (PET) cords sized with anaqueous adhesive composition according to the invention and a dieneelastomer composition, in comparison with a control cord sized with aconventional adhesive composition of the RFL type.

In the case of PET cords, it is known to precoat them in a first bathgenerally based on epoxy in aqueous solution, for example based onpolyglycerol polyglycidyl ether. The ingredients are introduced into thewater with stirring, for example in the following order: 0.5 per cent byweight of polyglycerol polyglycidyl ether (for example “Denacol EX-512”from Nagase Chemicals), 0.03 per cent by weight of surfactant (dioctylsodium sulphosuccinate, sold under the name “AOT 75”), 0.03 per cent byweight of sodium hydroxide and 99.44 per cent by weight of water.

The PET cords of these examples consist of folded yarns comprising twostrands of 144×2 (count of each strand equal to 144 tex) and 420/420(twist in t/m) construction; thus precoated, they are subsequently sizedwith aqueous adhesive compositions according to the invention and acontrol composition, and then dried in a drying oven at 140° C. for 30s. The adhesive composition was then crosslinked by passing the textilecords through a treatment oven at 240° C. for 30 s. They were thenrendered integral, by curing, with a natural rubber composition, asabove for the polyamide cords, by virtue of a vulcanization heattreatment, in order to form composite test specimens.

For these tests, three aqueous adhesive compositions were prepared asindicated above, two in accordance with the invention (hereinafterdenoted C-2.2 and C-2.3) and one not in accordance with the invention(control composition, hereinafter denoted C-2.1). Their formulations(expressed as percentage by weight) are presented in the appended Table2. The amounts listed in this table are those of the constituents in thedry state, with respect to a total of 100 parts by weight of aqueousadhesive composition (that is to say, the constituents plus the water).

The adhesive composition C-2.1 is a control composition, of RFL type,based on resorcinol and formaldehyde, commonly used to make PET fibresadhere to a rubber composition.

The aqueous adhesive composition C-2.2 according to the invention isbased on morin and 1,4-benzenedicarboxaldehyde.

The aqueous adhesive composition C-2.3 according to the invention isbased on phloroglucide and 1,3-benzenedicarboxaldehyde.

As above, these adhesive compositions C-2.1 to C-2.3 are furthermore allbased on NR, SBR and vinylpyridine/styrene/butadiene latexes.

The results of the adhesion tests (as described in the preceding sectionIII.1) carried out on the test specimens respectively prepared with theadhesive compositions C-2.1 to C-2.3 are summarized in Table 2.

The tearing-out force (F_(max)) for the cords according to the inventionsized with the adhesive compositions C-2.2 and C-2.3 according to theinvention admittedly exhibit a slightly lower value, both at 20° C. andat 120° C., than that of the control cord sized with RFL (arbitrarilyset at 100). However, these results are entirely acceptable for ensuringsatisfactory adhesive bonding of textile cords of PET type to a dieneelastomer composition.

In conclusion, the results of these various tests clearly demonstratethat the adhesive compositions according to the invention constitute ahighly advantageous alternative to the use of conventional RFLadhesives.

TABLE 1 Adhesive compositions C-1.1 C-1.2 C-1.3 C-1.4 Aldehyde:Formaldehyde (1) 0.9 — — — 1,3-Benzenedicarboxaldehyde (2) — — — 1.31,4-Benzenedicarboxaldehyde (3) — 1.2 1.3 — Polyphenol: Resorcinol (4)1.7 — — — Morin (5) — 1.4 — — Phloroglucide (6) — — 1.2 1.3 Sodiumhydroxide (7) 0.2 0.2 0.2 0.2 Elastomer latex: NR (8) 6.4 6.4 6.4 6.4SBR (9) 3.2 3.2 3.2 3.2 VP-SBR (10) 6.4 6.4 6.4 6.4 Aqueous ammonia (11)0.5 0.5 0.5 0.5 Total weight of dry matter of adhesive 19.3 19.3 19.319.3 composition Weight of water 80.7 80.7 80.7 80.7 Adhesion testsF_(max) at 20° C. 100 120 88 114 F_(max) at 120° C. 100 116 84 119 (1)Formaldehyde (from Caldic; diluted to 36%); (2)1,3-Benzenedicarboxaldehyde (from ABCR; purity of 98%); (3)1,4-Benzenedicarboxaldehyde (from ABCR; purity of 98%); (4) Resorcinol(from Sumitomo; purity of 99.5%); (5) Morin (from Fluka); (6)Phloroglucide (from Alfa Aesar; purity of 95%); (7) Sodium hydroxide(from Aldrich; diluted to 30%); (8) NR Latex (“Trang Latex” from Beetex; diluted to 61% by weight); (9) SBR Latex (“Encord-201” fromJubilant; diluted to 41% by weight); (10)Vinylpyridine/styrene/butadiene latex (“VP 106S” from Eliokem; dilutedto 41%); (11) Aqueous ammonia (from Aldrich; diluted to 21%).

TABLE 2 Adhesive compositions C-2.1 C-2.2 C-2.3 Aldehyde: Formaldehyde(1) 0.9 — — 1,3-Benzenedicarboxaldehyde (2) — — 1.31,4-Benzenedicarboxaldehyde (3) — 1.2 — Polyphenol: Resorcinol (4) 1.7 —— Morin (5) — 1.4 — Phloroglucide (6) — — 1.3 Sodium hydroxide (7) 0.20.2 0.2 Elastomer latex: NR (8) 6.4 6.4 6.4 SBR (9) 3.2 3.2 3.2 VP-SBR(10) 6.4 6.4 6.4 Aqueous ammonia (11) 0.5 0.5 0.5 Total weight of drymatter of adhesive 19.3 19.3 19.3 composition Weight of water 80.7 80.780.7 Adhesion tests F_(max) at 20° C. 100 87 92 F_(max) at 120° C. 10094 95 (1) Formaldehyde (from Caldic; diluted to 36%); (2)1,3-Benzenedicarboxaldehyde (from ABCR; purity of 98%); (3)1,4-Benzenedicarboxaldehyde (from ABCR; purity of 98%); (4) Resorcinol(from Sumitomo; purity of 99.5%); (5) Morin (from Fluka); (6)Phloroglucide (from Alfa Aesar; purity of 95%); (7) Sodium hydroxide(from Aldrich; diluted to 30%); (8) NR Latex (“Trang Latex” from Beetex; diluted to 61% by weight); (9) SBR Latex (“Encord-201” fromJubilant; diluted to 41% by weight); (10)Vinylpyridine/styrene/butadiene latex (“VP 106S” from Eliokem; dilutedto 41%); (11) Aqueous ammonia (from Aldrich; diluted to 21%).

The invention claimed is:
 1. An aqueous adhesive composition comprising:an unsaturated elastomer latex; and a phenol/aldehyde resin, wherein thephenol/aldehyde resin is based on at least: an aromatic polyaldehydebearing at least two aldehyde functional groups, the aromaticpolyaldehyde including at least one aromatic nucleus, and phloroglucide.2. The aqueous adhesive composition according to claim 1, wherein the atleast one aromatic nucleus of the aromatic polyaldehyde is a benzenenucleus.
 3. The aqueous adhesive composition according to claim 1,wherein the at least two aldehyde functional groups are borne by the atleast one aromatic nucleus.
 4. The aqueous adhesive compositionaccording to claim 3, wherein the aromatic polyaldehyde is selected froma group consisting of: 1,2-benzenedicarboxaldehyde,1,3-benzenedicarboxaldehyde, 1,4-benzenedicarboxaldehyde,2-hydroxybenzene-1,3,5-tricarbaldehyde, and mixtures thereof.
 5. Theaqueous adhesive composition according to claim 4, wherein the aromaticpolyaldehyde is 1,4-benzenedicarboxaldehyde.
 6. The aqueous adhesivecomposition according to claim 1, wherein the phenol/aldehyde resinincludes a basic solvent.
 7. The aqueous adhesive composition accordingto claim 6, wherein the basic solvent is an aqueous solution having a pHbetween 9 and
 13. 8. The aqueous adhesive composition according to claim1, wherein an unsaturated elastomer of the unsaturated elastomer latexis a diene elastomer selected from a group consisting of:polybutadienes, butadiene copolymers, polyisoprenes, isoprenecopolymers, vinylpyridine/styrene/butadiene terpolymers, and mixturesthereof.
 9. The aqueous adhesive composition according to claim 1,wherein a ratio by weight of the phloroglucide to the aromaticpolyaldehyde is between 0.1 and 3.0.
 10. The aqueous adhesivecomposition according to claim 1, wherein a content of thephenol/aldehyde resin as dry matter of the adhesive composition isbetween 5% and 60% by weight of the dry matter of the adhesivecomposition.
 11. The aqueous adhesive composition according to claim 1,wherein a content of unsaturated elastomer as dry matter of the adhesivecomposition is between 40% and 95% by weight of the dry matter of theadhesive composition.
 12. The aqueous adhesive composition according toclaim 1, wherein a ratio by weight of dry matter corresponding to thephenol/aldehyde resin to dry matter corresponding to the unsaturatedelastomer latex is between 0.1 and 2.0.
 13. The aqueous adhesivecomposition according to claim 1, wherein a water content of theadhesive composition is between 60% and 90% by weight of the aqueousadhesive composition.
 14. A textile material coated at least partiallywith an adhesive layer, the adhesive layer including an adhesivecomposition comprising: an unsaturated elastomer latex; and aphenol/aldehyde resin, wherein the phenol/aldehyde resin is based on atleast: an aromatic polyaldehyde bearing at least two aldehyde functionalgroups, the aromatic polyaldehyde including at least one aromaticnucleus, and phloroglucide.
 15. The textile material according to claim14, wherein the adhesive composition is an aqueous adhesive composition.16. The textile material according to claim 14, wherein the textilematerial has been dried.
 17. The textile material according to claim 14,wherein the textile material is a material selected from a groupconsisting of: films, monofilaments, multifilament fibres, assemblies ofmonofilaments or multifilament fibres, and mixtures thereof.
 18. Thetextile material according to claim 14, wherein the textile material isformed of a substance that includes a thermoplastic polymer.
 19. Thetextile material according to claim 18, wherein the thermoplasticpolymer is an aliphatic polyamide or a polyester.
 20. A rubber compositereinforced with a textile material coated at least partially with anadhesive layer, the adhesive layer including an adhesive compositioncomprising: an unsaturated elastomer latex; and a phenol/aldehyde resin,wherein the phenol/aldehyde resin is based on at least: an aromaticpolyaldehyde bearing at least two aldehyde functional groups, thearomatic polyaldehyde including at least one aromatic nucleus, andphloroglucide.
 21. The rubber composite according to claim 20, whereinthe rubber composite is incorporated in a tire.
 22. An adhesivecomposition comprising: an unsaturated elastomer latex; and aphenol/aldehyde resin, wherein the phenol/aldehyde resin is based on atleast: an aromatic polyaldehyde bearing at least two aldehyde functionalgroups, the aromatic polyaldehyde including at least one aromaticnucleus, and phloroglucide.
 23. The adhesive composition according toclaim 22, wherein the adhesive composition is in an uncured state. 24.The adhesive composition according to claim 22, wherein the adhesivecomposition is in a cured state.